Metamorphic Or Sedimentary Depending On Local Grade

Banded agate / chalcedony (likely iron-stained agate)

Microcrystalline quartz, SiO₂; varieties include chalcedony and jasper

Tumbled Rose Quartz

Quartz (Silicon Dioxide, SiO2 with trace amounts of titanium, iron, or manganese)

Tumbled greenstone or serpentine pebble

Likely serpentinite, composed mainly of serpentine-group minerals (antigorite/lizardite); identification is uncertain from the image alone

Pyrite

Iron Sulfide (FeS2)

Engraved polished dark stone (likely slate or basalt)

Probable fine-grained slate (microcrystalline phyllosilicates), possibly basalt; exact identification requires testing

Blue-green glassy mineral specimen, likely turquoise-colored fluorite or dyed material

Uncertain; possible fluorite (CaF₂), chrysocolla, or dyed calcite/glass

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Quartz

Silicon dioxide (SiO2)

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Red faceted gemstone, possibly ruby (identification uncertain)

Ruby, if natural: corundum (Al₂O₃) colored by chromium

Anthracite Coal

Anthracite

Orthoclase Feldspar

Potassium aluminum silicate (KAlSi3O8)

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Banded chert (likely flint or jasperoid)

Microcrystalline quartz/chalcedony, SiO₂

Schist (Kyanite Schist)

Kyanite-Mica Schist (primarily Al2SiO5, KAl2(AlSi3O10)(OH)2, and SiO2)

Chrysoprase-bearing serpentine (probable)

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄, with possible nickel-bearing chrysoprase/opal and iron oxides

Schist

Schist (metamorphic rock)

Quartz vein in iron-stained host rock

Quartz (SiO₂) with limonite/goethite staining, likely in altered basalt or another dark volcanic host

Coal (Anthracite)

Anthracite (Carbon-based organic sedimentary/metamorphic rock)

Quartz

Silicon Dioxide (SiO2)

Quartz Boulder

Silicon Dioxide (SiO2)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Banded Gneiss

Banded Gneiss (High-grade Metamorphic Rock)

Gneiss (specifically Micaceous Gneiss)

Gneiss (High-grade Regional Metamorphic Rock)

Pebble (river rock/beach pebble)

Pebble (clast size class)

Green Aventurine

Aventurine (Silicon dioxide, SiO₂)

Feldspathic Gneiss

High-grade Metamorphic Rock (Gneiss)

Gneiss

High-grade metamorphic rock (Gneiss)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Quartz Pebble

Silicon Dioxide (SiO2)

Chrome Diopside

Magnesium Calcium Silicate (MgCaSi2O6) containing Chromium impurities

Sandstone or Quartzite

Arenite (if sedimentary) / Quartzite (if metamorphic)

Lapis Lazuli

Lazurite-rich metamorphic rock ((Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Polished banded gneiss pebble

Gneiss, chiefly quartz–feldspar–mica; exact mineralogy uncertain from image

Granite Gneiss

Gneiss (containing quartz, alkali feldspar, plagioclase, biotite/amphibole)

Gneiss

Gneiss (Metamorphic rock composed primarily of quartz, feldspar, and mica)

Gneiss

Gneiss

Slate

Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)

Banded Gneiss

Gneiss (SiO2 enriched metamorphic rock)

Likely iron-rich quartzite or ironstone pebble

Quartz-rich rock with iron-oxide staining; exact identification requires examination

Biotite-rich schist (mica schist)

Mica schist, chiefly quartz + biotite mica; approximate formula for biotite K(Mg,Fe)3AlSi3O10(F,OH)2

Blue Sapphire

Corundum (Al2O3)